JPH027237A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To always perform the optimum recording by reading out a data part with a second beam spot, comparing the mean level of the spots with a reference value by detecting by a low-pass filter, and controlling the recording power level of a preceding recording beam. CONSTITUTION:Date reproduced by the beam spot 3 is inputted to the low-pass filter 5, and is compared with the voltage of a reference power source 7 by a differential amplifier circuit 6, and deviation from the optimum level of a reproducing level is detected. At an adder amplifier circuit 8, addition on the voltage of a second reference power source 9 equivalent to the recording power level of the beam spot 2 is performed, and a laser diode corresponding to the beam spot 2 is driven via an LD driver 10. In such a way, it is possible to always perform the recording with the optimum condition for the reproduction of the data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording/reproducing apparatus that records information on a recording medium using optical means or reproduces recorded information.

[Conventional technology]

In an optical disk memory, a laser beam is used as a light source, and this laser beam is modulated with a pulsed signal from an external information source to record binary information on a recording medium on a disk, or to read recorded information. When recording, a predetermined value is used as the recording power level of a normal laser diode, and information is recorded in 1 to 1 racks on the surface of the medium.

When data is recorded on the entire surface of the disk using this set recording power level, data cannot be optimally recorded from the inner circumference to the outer circumference of the disk because the circumferential speed of the disk track varies depending on the disk radius. This effect is particularly noticeable in optical discs that utilize heat mode. Therefore, attempts have been made to solve the above-mentioned problem by dividing the disk into blocks in the radial direction and performing recording by setting optimal recording conditions for each block.

[Problem to be solved by the invention]

However, even with this recording method using block division,
Optimal recording conditions vary depending on variations between devices, variations between discs, or the state of the recording device at that time. In this way, if the recording conditions deviate from the optimal state, 1
Even if various corrections are made, the reproduction margin will be reduced and bit errors will increase. In particular, when performing multilevel recording using the partial response method,
There is a problem in that it is necessary to accurately define the intermediate level of the reproduced analog signal, and the recording conditions must always be kept optimal.

The purpose of the present invention is to solve these problems and to constantly maintain recording conditions at optimum values using two beams.
An object of the present invention is to provide an optical information recording and reproducing device that can perform more accurate recording and reproducing.

[Means to solve the problem]

The configuration of the present invention uses an optical head that sequentially irradiates two light beams from a plurality of laser diodes or laser arrays onto the same track of a recording medium to form first and second beam spots. In an optical information recording and reproducing apparatus that records information using the preceding first beam spot and reproduces the recorded information using the second beam spot, a low-pass filter that detects the frequency components;
A differential amplifier circuit that outputs the difference between the output of the low-pass filter and a reference signal, and a recording power level control circuit that controls the optical output of the first light beam during recording using the output of the differential amplifier circuit. It is characterized in that the reproduced signal from the second beam spot has a constant value.

[Effect]

According to the configuration of the present invention, the data portion recorded using the preceding beam spot is read out using the second beam spot that follows the preceding beam, and the average level of the reproduced signal is detected by a low-pass filter. By comparing with a reference value and controlling the recording power level of the preceding recording beam so that it is equal to this reference value level, optimal recording is always achieved regardless of disc radial direction, disc variations, and device variations. It can be performed.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. two beam spots 2 generated by the optical bed 1;
3 is positioned on the track 12 of the disk 11 by a focus tracking control system (not shown). At this time, the disk rotates in the direction shown by arrow 13, data is recorded with beam spot 2, and then the recorded data is reproduced with beam spot 3.

The data reproduced by beam spot 3 is transmitted to reproduction amplifier 4.
The signal is input to the low-pass filter 5 via the input signal, and a signal indicating the average value of the reproduced data is output. This average value signal is compared by the differential amplifier circuit 6 with the voltage of a predetermined first reference power supply 7 corresponding to, for example, the intermediate level of three-level level detection using the partial response method, and the difference signal is The signal is input to the summing amplifier circuit 8. This makes it possible to detect the deviation of the reproduction level from the optimum level when data recorded with beam spot 2 is reproduced.

In the addition amplifier circuit 8, a predetermined beam spot 2
The voltage of the second reference power source 9 corresponding to the recording power level of is added to the voltage of the second reference power source 9, and the added signal also drives the laser diode corresponding to the beam spot 2 via the LD driver. As a result, the predetermined recording power level can be dynamically corrected to the optimal recording power level, and more accurate signal reproduction can be achieved. When recording data, the average level of the reproduced signal changes depending on the data pattern, but the recorded data is usually precoated before being recorded and processed to prevent DC level fluctuations from occurring regardless of the data pattern. Therefore, the average value does not vary depending on the pattern.

〔Effect of the invention〕

As described above, according to the present invention, variations between devices,
Regardless of discrepancies between disks or the condition of the device,
Recording can always be performed under optimal conditions for data reproduction, and more accurate and reliable recording and reproduction can be performed.

truck, 3...Arrow in direction of rotation.

Claims (1)

[Claims] Using an optical head that sequentially irradiates two light beams from a plurality of laser diodes or laser arrays onto the same track of a recording medium to form first and second beam spots, the preceding first beam spot is In the optical information recording and reproducing apparatus that records information by using the second beam spot and reproduces the recorded information using the second beam spot, the optical information recording and reproducing apparatus includes: a low-pass filter that detects a low-frequency component of the signal reproduced by the second beam spot; , a differential amplifier circuit that outputs the difference between the output of the low-pass filter and a reference signal, and a recording power level control circuit that controls the optical output of the first light beam during recording using the output of the differential amplifier circuit. An optical information recording/reproducing apparatus comprising: a reproduction signal from the second beam spot having a constant value.